Osteoporosis is a well known condition which results from decreased bone mass involving a process of loss of both bone mineral and protein matrix components. This disease condition occurs in a number of situations, and most commonly in situations where there is an estrogen deficit, such as, in postmenopausal women; situations involving an excess of catabolic hormone such as is found in Cushing's disease; in situations involving long term administration of corticosteroids; and in situations where a patient is immobilized. Osteoporosis is also known to occur in certain patients with liver disease, gonadal dysgenesis, and osteogenesis imperfecta, which is an inherited condition in which the bones are abnormally brittle and subject to fractures. Osteoporosis can be detected by overt signs or by X-ray examination. Overt indicators include pain in the weight-bearing vertebrae, local tenderness and pain if a fracture has occurred, loss in height, and an increase in calcium levels in the urine which eventually decline as bone calcium resevoirs are depleted.
Current methods of treatment include exercise, providing the patient with physical support to reduce the weight stress on the skeletal structure, estrogen therapy, particularly for postmenopausal women, and consumption of calcium or calcium containing substances such as milk. Except in situations where Cushing's disease has been successfully treated none of the current methods of treating osteoporosis results in restoration of bone mass. The invention described and claimed herein provides for a method of treating demineralized bone conditions whereby there is a restoration of the bone mass. Bone cells are of two types: osteoblasts which are associated with bone production; and osteoclasts which are associated with bone absorption and removal. It is believed that the compounds employed in the present invention decrease the number of osteoclasts and stimulate the metabolic activity of the osteoblasts, and/or increase the size of the osteoblasts. Nevertheless, that the compounds employed in the present invention are having an effect on the osteoclast activity is not being ruled out. As will become apparent from the information provided below a surprising aspect of this invention is the dosage at which the compounds are effective in increasing bone mass.